Tornadoes cannot collapse in on themselves. In many cases a tornado will become much narrower as it enters its dissipating stage, and is said to be "roping out." During this stage the winds in the tornado may actually speed up as angular momentum is conserved. It is still considered a tornado until it dissipates completely.
calderacalderaIt forms a caldera.
CALDERA
It forms a 'caldera'.
The tornado itself is a whirling circular mass of air. Condensation of water droplets at the tornado's core forms the funnel.
A tornado moves with its parent thunderstorm. The storm itself is carried by the winds in the environment it forms in.
When a volcano collapses on itself a caldera is then formed.
A storm does not become a tornado; it produces one. The rest of the storm remains largely unchanged as a cumulonimbus cloud. The tornado itself forms a funnel cloud.
When rock above a cave collapses, a sinkhole is formed.
Caldera
another floor
A caldera
When a volcano collapses on itself a caldera is then formed.